The traditional means for removably attaching single or dual wheels to heavy truck axles involves a hub with hardened steel lugs pressed through its circumference which extend through aligned holes in the metal wheel and are secured thereto by single or double lug nuts. These removable components oft times weld together or bind due to corrosion and/or metal transfer, and efforts to separate them result in damage thereto.
Typically, water and road salts in the operating environment aid in the formation of corrosion/rust on the holding thread and/or splines of the wheel studs, so that the lugs become stuck on the wheel studs or the wheel studs become stuck in the hub. As a result, the studs have to be removed and replaced in order to prevent the wheel from becoming detached from the hub.
The use of fasteners with corrosion-inhibiting, fitted washers, such as J. E. Jones U.S. Pat. No. 3,574,080 and K. J. Shomber U.S. Pat. No. 3,060,112, or merely using washers made of non-conductive material between the components of the fastener assembly and the components to be fastened together, are known and utilized in the aviation industry and other high-tech assemblies. The unique arrangement of the components for removably attaching wheels to hubs on an axle of a heavy-duty truck place steel, steel alloys, and other dissimilar metals in close proximity, so a galvanic coupling is set up in the operating environment. The transfer of metal results in such corrosion that the lug can weld to the threaded end of the wheel stud or to the longitudinal splines on the end of the wheel stud pressed into the hub and the hubs corresponding mating splines. The problem of welding or corrosion of these components is that the components may be damaged in order to separate them for regular maintenance. This condition is what gave rise to W. H. Oliver U.S. Pat. No. 3,330,177, an impact cap for the threaded end of the wheel lug, to protect it when it is driven out of the wheel hub.